Occupational lung disease

Question 1

Which chemicals are associated with occupational asthma

Answer 1

isocyanates (most common): spray painting and foam moulding using adhesives
platinum salts
soldering flux resin
glutaraldehyde
flour
epoxy resins
proteolytic enzymes

Question 2

Clinical features of occupational asthma and investigations

Answer 2

S/S of asthma that are better at weekends/when away from work

Ix
Serial measurements of peak expiratory flow are recommended at work and away from work
Referral should be made to a respiratory specialist for patients with suspected occupational asthma.

Question 3

Define pneumoconiosis and its types

Answer 3

Group of fibrosing interstitial lung diseases, mostly of occupational origin, that is caused by the inhalation of mineral or metal dusts.

Simple: coal worker’s pneumoconiosis or silicosis (symptom-free)
Complicated: Pneumoconiosis results in loss of lung function
Asbestosis: Pneumoconiosis in which diffuse parenchymal lung fibrosis occurs as a result of prolonged exposure to asbestosis

Question 4

Aetiology and risk factors of pneumoconiosis

Answer 4

Silica, coal, beryllium, asbestos

→ development of round fibrotic masses in the upper lungs

Silica:. mining, quarrying, iron and steel foundries, manufacture of ceramics, cement cutting, hydraulic fracking
Coal e.g. coal mining
Beryllium e.g. manufacturing of master alloy (copped and beryllium) used for circuitry and heat-resistant ceramics, dental prostheses and metal products

Question 5

Symptoms of pneumoconiosis

Answer 5

Lag time between occupation and expression = 15-20 years

Dyspnoea on exertion
Cough
Chest tightness, wheeze
Haemoptysis, fever, night sweats
Weight loss
Melanoptysis (coal worker’s)
Pleuritic chest pain

Question 6

Signs of pneuconiosis on examination

Answer 6

Cyanosis
Clubbing
Signs of rheumatoid arthritis, scleroderma or renal failure

Barrel chest
Crackles on auscultation
Areas of dullness on percussion due to pleural effusion due to cor pulmonale
Prolonged expiration and wheezing

Question 7

Investigations for pneumoconiosis

Answer 7

CXR:
- Micronodular mottling → nodular opacities (fibrosis) in the UPPER LOBES
- Eggshell calcification of hilar lymph nodes (silicosis)
- Bilateral lower zone reticulonodular shadowing and pleural plaques (asbestosis)

Spirometry: restrictive (FEV1/FVC ratio normal, both reduced)
CT: fibrotic change (upper zone)
Beryllium lymphocyte proliferation test (BeLPT)
Bronchoscopy: granulomas (beryllium)
Tuberculin skin testing: for everyone with silicosis

Question 8

Management for pneumoconiosis

Answer 8

Avoid exposure to coal dust and other respiratory irritants (e.g. Smoking).
Patients may be eligible for compensation via the Industrial Injuries Act
Manage fibrosis:

Conservative:
Physiotherapy
Pulmonary rehabilitation: exercise programme to cope with SOB
Modify risk factors: smoking cessation
Prevention of exacerbations/complications:
- Vaccination (pneumococcal & seasonal flu vaccination)
- Regular exercise (150min/week)
- Avoid being around people with chest infections / colds

Medical:
LTOT
N-acetyl-cysteine → breaks up lung mucous
Pirfenidone OR Nintedanib → reduced rate of fibrosis, anti-oxidant, anti-fibrotic

Question 9

Complications for pneumoconiosis

Answer 9

COPD, lung cancer, acute bronchitis, pneumonia
Cor pulmonale
Chronic renal failure
Rheumatoid arthritis, scleroderma, Granulomatosis with polyangiitis
TB

Question 10

Prognosis for pneumoconiosis

Answer 10

Prolonged exposure can lead to irreversible pulmonary fibrosis
The disease can progress even after cessation of exposure